阅读说明：本技术 制备组分可调的二维h-BNC杂化薄膜的方法 (Method for preparing two-dimensional h-BNC hybrid film with adjustable components ) 是由 孟军华 张兴旺 程立昆 尹志岗 吴金良 于 2019-05-09 设计创作，主要内容包括：本发明提供了一种制备组分可调的二维h-BNC杂化薄膜的方法。该方法包括：准备衬底并将衬底置于离子束溅射沉积系统内；预抽背底真空,然后在氢气气氛中对衬底进行升温并退火；退火结束后关闭氢气使腔室恢复至真空环境,然后向腔室内通入甲烷和氩气；利用离子源产生氩离子束,轰击烧结的氮化硼靶材同时将甲烷裂解,使得硼、氮、碳原子在衬底表面沉积,形成二维h-BNC杂化薄膜；生长结束后,关闭甲烷气体、加热源使样品随炉降温,最终得到二维h-BNC杂化薄膜。本发明制备二维h-BNC杂化薄膜的方法,不仅可以有效避免前驱体不稳定、副产物多等问题,而且可控性好,制备的薄膜均匀性好。(The invention provides a method for preparing a two-dimensional h-BNC hybrid film with adjustable components. The method comprises the following steps: preparing a substrate and placing the substrate in an ion beam sputtering deposition system; pre-vacuumizing the back substrate, then heating the substrate in a hydrogen atmosphere and annealing; after the annealing is finished, closing the hydrogen to restore the chamber to a vacuum environment, and then introducing methane and argon into the chamber; generating argon ion beams by using an ion source, bombarding the sintered boron nitride target material and cracking methane at the same time, so that boron, nitrogen and carbon atoms are deposited on the surface of the substrate to form a two-dimensional h-BNC hybrid film; and after the growth is finished, closing methane gas and a heating source to cool the sample along with the furnace, and finally obtaining the two-dimensional h-BNC hybrid film. The method for preparing the two-dimensional h-BNC hybrid film can effectively avoid the problems of instability of the precursor, more byproducts and the like, and has good controllability and good uniformity of the prepared film.)

1. A method of making a two-dimensional h-BNC hybrid thin film, comprising:

preparing a substrate and placing the substrate in an ion beam sputtering deposition system;

pre-pumping the back substrate of the ion beam sputtering deposition system to be vacuum, and then heating and annealing the substrate in a hydrogen atmosphere;

after the annealing is finished, closing hydrogen to restore the chamber of the ion beam sputtering deposition system to a vacuum environment, and then introducing methane and argon into the chamber;

an ion source is used for generating argon ion beams to bombard the sintered boron nitride target material and simultaneously crack methane, so that boron, nitrogen and carbon atoms are deposited on the surface of the substrate, and a two-dimensional h-BNC hybrid film is grown;

and after the growth of the two-dimensional h-BNC hybrid film is finished, closing methane gas and cooling to finally obtain the two-dimensional h-BNC hybrid film.

2. The method for preparing a two-dimensional h-BNC hybrid film according to claim 1, wherein the step of preparing a substrate comprises:

the substrate is put in dilute nitric acid for pretreatment, then washed by deionized water, sequentially placed in acetone, isopropanol and ethanol for ultrasonic cleaning, and dried by nitrogen for standby.

3. The method for preparing a two-dimensional h-BNC hybrid film according to claim 2, wherein the dilute nitric acid concentration is between 5 wt% and 10 wt% and the etching time is between 5s and 40 s.

4. The method for preparing the two-dimensional h-BNC hybrid film according to claim 1, wherein the substrate is a transition metal or alloy substrate.

5. The method for preparing a two-dimensional h-BNC hybrid film according to claim 1, wherein the purity of the boron nitride target material is more than 99.5%.

6. The method for preparing two-dimensional h-BNC hybrid film according to claim 1, wherein the annealing temperature is between 950 ℃ and 1150 ℃, the hydrogen flow rate is between 10sccm and 50sccm, and the annealing time is between 10min and 30 min.

7. The method for preparing the two-dimensional h-BNC hybrid film according to claim 1, wherein the flow rate of argon gas introduced is between 3sccm and 10sccm, and the flow rate of methane is between 1sccm and 30 sccm.

8. The method for preparing a two-dimensional h-BNC hybrid film according to claim 1, wherein the ion beam current density is between 0.1mA/cm²To 0.4mA/cm²And the growth time is between 5min and 15 min.

9. The method for preparing the two-dimensional h-BNC hybrid film according to claim 1, wherein the BN/C ratio in the film is continuously adjusted from 0-100% by adjusting the methane flow and the ion beam current density.

Technical Field

The invention relates to the technical field of material science, in particular to a method for preparing a two-dimensional h-BNC hybrid film with adjustable components.

Background

In recent years, two-dimensional layered materials have been studied due to their thickness at atomic level, unique low-dimensional structure, and many excellent physical, chemical, and electronic properties. Graphene is a typical representative of two-dimensional layered materials, has ultrahigh carrier mobility, high thermal conductivity, high chemical stability, good mechanical properties and the like, and shows potential application prospects in the fields of electronic devices and circuits. However, due to the lack of band gap, graphene-based field effect transistors often cannot be turned off, severely impacting their practical electronics applications.

With the development of graphene research, other two-dimensional layered materials are gradually coming into the visual field of people, wherein hexagonal boron nitride (h-BN) is gradually becoming another bright point in the field. The h-BN is an isoelectric substance of graphene, has the same lattice structure with the graphene, has a lattice constant close to that of the graphene, and has a lattice mismatch degree of only 1.7 percent. But due to the different distribution of the extra-nuclear electrons, the two exhibit distinct band structures and electrical properties: the graphene is a zero-band-gap semimetal with excellent conductivity, and the forbidden band width of h-BN reaches 5.97eV, so that the graphene has good electrical insulation. The structural similarity and complementarity of properties allow both to form lateral heterostructures or h-BNC ternary hybrid films within a single atomic layer. Theoretical research shows that when the two materials form an in-plane structure, the electrical and transport properties of graphene are modulated by h-BN, and the band gap of the graphene is opened under the influence of an interface quantum confinement effect and a spin polarization effect. Particularly for the in-plane hybrid h-BNC film, the adjustable electrical properties of the film from an insulator to a semiconductor can be realized by changing the proportion and distribution of graphene and h-BN. Actually, experiments prove that the field effect transistor based on the two-dimensional h-BNC hybrid film can not only keep the higher carrier mobility of graphene, but also keep a larger on-off ratio of the device due to the band gap of the film, and is expected to solve the bottleneck problem of the graphene electronic device.

The preparation of high-quality h-BNC materials is the basis and precondition for property research and device application. At present, two-dimensional h-BNC hybrid films are prepared based on a Chemical Vapor Deposition (CVD) method, an in-situ electron beam irradiation method and the like, but the problems of unstable precursors, high price, difficulty in control of correlation of growth parameters and the like still exist, and on the other hand, the quality and uniformity of the hybrid films are still to be improved.

Disclosure of Invention

Technical problem to be solved

To solve one or more of the above problems, the present invention provides a method for preparing a two-dimensional h-BNC hybrid film with tunable composition.

(II) technical scheme

According to an aspect of the present invention, there is provided a method of preparing a two-dimensional h-BNC hybrid thin film, comprising:

preparing a substrate and placing the substrate in an ion beam sputtering deposition system;

pre-pumping the back substrate of the ion beam sputtering deposition system to be vacuum, and then heating and annealing the substrate in a hydrogen atmosphere;

after the annealing is finished, closing hydrogen to restore the chamber of the ion beam sputtering deposition system to a vacuum environment, and then introducing methane and argon into the chamber;

an ion source is used for generating argon ion beams to bombard the sintered boron nitride target material and simultaneously crack methane, so that boron, nitrogen and carbon atoms are deposited on the surface of the substrate, and a two-dimensional h-BNC hybrid film is grown;

and after the growth of the two-dimensional h-BNC hybrid film is finished, closing methane gas and cooling to finally obtain the two-dimensional h-BNC hybrid film.

In a further embodiment, the step of preparing the substrate comprises:

the substrate is put in dilute nitric acid for pretreatment, then washed by deionized water, sequentially placed in acetone, isopropanol and ethanol for ultrasonic cleaning, and dried by nitrogen for standby.

In a further embodiment, the dilute nitric acid concentration is between 5 wt% and 10 wt% and the etch time is between 5s and 40 s.

In further embodiments, the substrate is a transition metal or alloy substrate.

In further embodiments, the purity of the boron nitride target is greater than 99.5%.

In a further embodiment, the annealing temperature is between 950 ℃ and 1150 ℃, the hydrogen flow rate is between 10sccm and 50sccm, and the annealing time is between 10min and 30 min.

In a further embodiment, the flow of argon is between 3sccm to 10sccm and the flow of methane is between 1sccm to 30 sccm.

In a further embodiment, the ion beam current density is between 0.1mA/cm²To 0.4mA/cm²And the growth time is between 5min and 15 min.

In a further embodiment, the BN/C ratio in the film is continuously adjusted from 0-100% by adjusting the methane flow and the ion beam current density.

(III) advantageous effects

According to the technical scheme, the method for preparing the two-dimensional h-BNC hybrid film with adjustable components has at least the following beneficial effects:

(1) according to the invention, the two-dimensional h-BNC hybrid film is prepared based on the ion beam assisted deposition method, methane is used for providing a carbon source, and the sintered boron nitride target material is used for providing a BN source, so that the problems of instability of a precursor, more byproducts and the like can be effectively avoided;

(2) the invention realizes the component adjustment of the h-BNC film by adjusting the methane flow and the ion beam current density, has good controllability, and the prepared film has good uniformity.

Drawings

FIG. 1 is a flow chart for preparing a two-dimensional h-BNC hybrid film provided by the invention;

FIG. 2 is a schematic view of an apparatus for preparing a two-dimensional h-BNC hybrid film by an ion beam assisted deposition method according to the present invention;

FIG. 3 is an SEM image of a two-dimensional h-BNC hybrid film prepared according to an embodiment of the invention.

Detailed Description

In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.

The method is based on an ion beam assisted deposition method, adopts argon ion beam sputtering sintering, generates B, N source from boron nitride target material, and introduces a certain amount of methane to provide carbon source in the growth process, grows the two-dimensional h-BNC hybrid film, and realizes component adjustment of the h-BNC film by adjusting the methane flow and the ion beam current density, thereby preparing the high-quality two-dimensional h-BNC hybrid film.

FIG. 1 shows a flow chart of a method for preparing a two-dimensional h-BNC hybrid film with tunable components provided by the invention. As shown in fig. 1, the method comprises the following specific steps:

step A, preparing a substrate, and placing the substrate in an ion beam sputtering deposition system;

the method comprises the following steps: and (2) pretreating the cut substrate in dilute nitric acid with a certain concentration for a period of time, washing the substrate by using deionized water, then sequentially placing the substrate in acetone, isopropanol and ethanol for ultrasonic cleaning, finally drying the substrate by using nitrogen, and then installing the substrate into an ion beam sputtering substrate system for later use.

In this step, the substrate is selected from one of the following materials: copper foil, nickel foil, copper nickel alloy, or other transition metal foil or thin film substrate, preferably the substrate is copper foil. Besides nitric acid, ferric chloride etching solution can be used as the etching solution, and the concentration and the etching time of the etching solution can be selected by those skilled in the art according to needs, preferably, the nitric acid concentration is between 5 wt% and 10 wt%, and the etching time is between 5s and 40 s.

And step B, pre-pumping the back substrate of the ion beam sputtering deposition system to be vacuum, and then heating and annealing the substrate in a hydrogen atmosphere.

In this step, to avoid high temperature oxidation of the substrate, the back substrate of the deposition chamber is pre-pumped to 1 × 10 in vacuum before the substrate is annealed at elevated temperature^-4And introducing hydrogen below Pa, heating and annealing. The annealing temperature is between 950 ℃ and 1050 ℃, preferablyThe annealing temperature is 1050 ℃, the hydrogen flow is between 10sccm and 50sccm, and the annealing time is between 10min and 30 min. In this embodiment, the annealing temperature is 1050 ℃, the hydrogen flow rate is 20sccm, and the annealing time is 20 min.

And step C, closing hydrogen after annealing is finished so that the chamber of the ion beam sputtering deposition system is restored to a vacuum environment, and then introducing methane and argon into the chamber.

In this step, argon gas is introduced from the ion source as a working gas to generate an argon ion beam, wherein the flow rate of the argon gas is between 3sccm and 10sccm, preferably the flow rate of the argon gas is 4sccm, methane is a carbon source, and the flow rate is adjustable between 1sccm and 30 sccm. The carbon content in the film is controlled by adjusting the flow rate of the methane. FIG. 2 shows a schematic diagram of an apparatus for preparing a two-dimensional h-BNC hybrid film by the ion beam sputtering deposition method in the invention.

And D, generating argon ion beams by using an ion source to bombard the sintered boron nitride target material and simultaneously cracking methane, so that boron, nitrogen and carbon atoms are deposited on the surface of the substrate, and growing the two-dimensional h-BNC hybrid film.

In the step, the ion source is a koffman ion source and is used for generating an argon ion beam and bombarding a sintered boron nitride target material, wherein the purity of the boron nitride target material is more than 99.5%, and the ion beam density is between 0.1mA/cm²To 0.4mA/cm²The growth time of the film is between 5min and 15min, and the growth temperature is 1050 ℃. The BN particles are sputtered more when the beam current density is larger, and the BN/C ratio in the h-BNC film can be adjusted from 0-100% by adjusting the ion beam current density and the methane flow. Wherein the thickness of the h-BNC film is adjusted by adjusting the growth time. In this example, the flow rate of methane was 9sccm, and the ion beam current density was 0.1mA/cm²The growth temperature is 1050 ℃ and the growth time is 7 min.

And E, after the growth of the two-dimensional h-BNC hybrid film is finished, closing methane gas and cooling to finally obtain the two-dimensional h-BNC hybrid film.

Wherein, the temperature reduction is to reduce the temperature of the sample along with the furnace through a heating source.

In order to realize the characterization and use of the h-BNC film, the h-BNC film is transferred onto different substrates after the growth is finished, and the transfer method is the same as the existing method for transferring graphene and h-BN, for example, the wet transfer method using PMMA, or the method using PDMS rubber imprinting, and the like, which have been widely reported in the prior art, and are not described herein again.

FIG. 3 is an SEM topography of a two-dimensional h-BNC hybrid film prepared according to an embodiment of the invention. As shown in FIG. 3, when the growth time of the two-dimensional h-BNC hybrid film is 7min, h-BNC domains with flat and uniform surfaces can be observed on the surface of the substrate, and the continuous h-BNC film can be obtained by continuously prolonging the growth time. In the growth process, the problems of instability of a precursor, more byproducts and the like are effectively avoided, the controllability is good, and the two-dimensional h-BNC hybrid film with good uniformity is finally prepared.

The method for preparing the two-dimensional h-BNC hybrid film with adjustable components is introduced.

In conclusion, the method for preparing the two-dimensional h-BNC hybrid film with adjustable components can simply and efficiently grow to obtain the two-dimensional h-BNC hybrid film, has simple growth process and good controllability, and effectively avoids the problems of unstable precursor, difficult growth control and the like in other methods. Meanwhile, the component regulation and control of the two-dimensional h-BNC hybrid film can be effectively realized by controlling the methane flow and the ion beam current density.

It should be noted that in the drawings or description, the same drawing reference numerals are used for similar or identical parts. Implementations not depicted or described in the drawings are of a form known to those of ordinary skill in the art. Additionally, while exemplification of parameters including particular values may be provided herein, it is to be understood that the parameters need not be exactly equal to the respective values, but may be approximated to the respective values within acceptable error margins or design constraints.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.